Gloomlake Verge

{T}: Add {U}.
{T}: Add {B}. Activate only if you control an Island or a Swamp.

Underground River

{T}: Add {C}.
{T}: Add {U} or {B}. This land deals 1 damage to you.

{T}: Add one mana of any color in your commander's color identity.

This land enters tapped unless you control an Island or a Swamp.
{T}: Add {U} or {B}.

This land enters tapped unless you control two or more other lands.
{T}: Add {U} or {B}.

({T}: Add {U} or {B}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

This land enters tapped unless you have two or more opponents.
{T}: Add {U} or {B}.

Each land is a Swamp in addition to its other land types.

{T}: Add {C}.
{T}: Add {U} or {B}. This artifact deals 1 damage to you.

This land enters tapped.
When this land enters, exile target player's graveyard.
{T}: Add {B}.